Question

The rate of increase in population is 20% per annum. What will be the population after 3 years if the initial population is 32,000?

• A. 55,346
• B. 55,296
• C. 55,426
• D. 55,456

Answer 1

The correct option is B

55,296

The rate of increase in population is the increase in population compared to the previous year.
We use the concept of compound interest to find the population after two years.

A = P × ${[1+\frac{R}{100}]}^n$

where, A = population after two years

P = initial population = 32,000

Time (n) = 3 years

Rate (R) = 20%

$\therefore$ A = 32,000 × ${[1+\frac{20}{100}]}^3$ = 55,296

After 3 years the population will be 55,296.